Wednesday, September 22, 2021

[Mammalogy • 2021] Molossus melini • A New Species of Molossus (Chiroptera: Molossidae) from Argentina, in the Pampa Ecoregion


Molossus melini
Montani, Tomasco, Barberis, Romano, Barquez & Díaz, 2021

 
Abstract
Fourteen species of bats in the genus Molossus currently are recognized in the Neotropical region; only three are known from Argentina. Here, we describe a new species based on specimens collected in the province of Santa Fe, Argentina, in the Pampa ecoregion. The new species can be distinguished from its congeners by its general strong orange coloration, forearm length > 41 mm, dorsal hairs bicolor and long (~5 mm), infraorbital foramen laterally oriented, and long and forward-projected (pincer-like) upper incisors. The external and cranial morphology of the new species are described and comparisons made with other species of similar size and with those present in its distributional area. Wilcoxon tests and multivariate analyses (nonmetric multidimensional scaling ordination and PERMANOVA) were carried out to determine the morphometric differences between the new species and other seven species of Molossus. The species tree, estimated by *BEAST from the concatenation of mitochondrial and nuclear genes, suggests that Molossus sp. nov. is basal within the clade formed by {{M. aztecus, M. rufus}, {{M. currentium, M. pretiosus}, M. sinaloae}} with a posterior probability of 0.82.

Keywords: Argentina, Molossus, new species, Pampa ecoregion, Santa Fe province

skull of the holotype of Molossus melini (MG-ZV-M 339).
Scale bar = 5 mm.

Molossus melini
 the paratype alive (MG-ZV-M 338) in the type locality.

Family Molossidae Gervais, 1856

Genus Molossus É. Geoffroy St.-Hilaire, 1805

Molossus melini sp. nov.

Etymology: The name melini is in reference to Cacique Melin, leader of “Los Ranqueles,” an indigenous tribe from the region, who was murdered on the shores of the Melincué lagoon (named for Melin and his son, Cue, also killed in the same battle), near the type locality of the species. Many local legends surround these indigenous people and the lagoon.


M. Eugenia Montani, Ivanna H. Tomasco, Ignacio M. Barberis, Marcelo C. Romano, Rubén M. Barquez and M. Mónica Díaz. 2021. A New Species of Molossus (Chiroptera: Molossidae) from Argentina. Journal of Mammalogy. gyab078. DOI: 10.1093/jmammal/gyab078

Se reconocen actualmente 14 especies de Molossus en el Neotrópico, de las cuales tres están presentes en Argentina. Describimos en el presente trabajo una especie nueva de este género sobre la base de ejemplares procedentes de la ecorregión Pampeana de la provincia de Santa Fe, Argentina. La nueva especie se distingue de las otras especies de Molossus por su coloración general fuertemente anaranjada, longitud del antebrazo > 41 mm, pelos dorsales largos (~5 mm) y bicolores, foramen infraorbitario orientado lateralmente, e incisivos superiores largos y proyectados anteriormente como pinzas. Incluimos la descripción de la morfología externa y craneal de la nueva especie, comparando esta última con especies similares, así como con aquellas presentes en su área de distribución. Llevamos a cabo pruebas de Wilcoxon y análisis multivariados (NMDS y PERMANOVA) para determinar las diferencias morfométricas entre la nueva especie y otras siete especies de Molossus. El árbol de especies, estimado por *BEAST a partir de la concatenación de genes mitocondriales y nucleares, sugiere que Molossus sp. nov. se ubica, con una probabilidad posterior de 0.82, dentro del clado formado por {{M. aztecus, M. rufus}, {{M. currentium, M. pretiosus}, M. sinaloae}}.

Argentina, Ecorregión Pampeana, Molossus, nueva especie, provincia de Santa Fe

[Paleontology • 2021] Early Palaeozoic Discinocarina: A Key to the Appearance of Cephalopod Jaws


general view of the cephalic region of an orthocerid in an attacking position.
 The Aptychopsis is working as a protective shield, the dorsal plate is displaced to open the mouth with a radula on a short proboscis. The number of arms (ten) is based on Shigeno et al. 2008, 2010. The presence of well-developed eyes in orthocerids is based on the molecular study of Nautilus eyes (Ogura et al. 2013).

in Mironenko, 2021. 

Reconstruction by Andrey Atuchin  deviantart.com/olorotitan

Abstract
Cephalopoda is the only class of molluscs in which virtually all its modern representatives have a pair of powerful jaws. There is little doubt that jaws have contributed to the evolutionary success of cephalopods, but their origin still remains a mystery. Though cephalopods appeared at the end of the Cambrian, the oldest unequivocal jaws have been reported to date from the Late Devonian, though they were initially interpreted as phyllopod crustaceans of the suborder Discinocarina. After their relation with ammonoids was proven, they were considered as opercula, and only later their mandibular nature was recognized and widely accepted. Finds of discinocarins from Silurian deposits are still considered as opercula of ammonoid ancestors - nautiloids of the order Orthocerida. However, according to modern ideas, there is no place within their soft body for the location of such large opercula. Moreover, the repeated appearance of very similar structures in the same evolutionary line at least twice, but in different places of the body and for different purposes seems highly improbable. A new hypothesis is proposed herein, in which the Silurian fossils, earlier assigned to Discinocarina, are not specialized opercula, but protective shields, to defend orthocerids not from the predators, but from their own prey. The chitinous plates around the mouth likely appeared in the Silurian orthocerids for protection from such damage and later, during Silurian and Devonian, most likely gradually evolved into the jaws.

Keywords: Anaptychi, aptychi, Aptychopsis, Cephalopoda, Discinocarina, jaw apparatus

Hypothetical reconstruction of Silurian Orthocerida with Aptychopsis as proto-jaws.
A, general view of the cephalic region of an orthocerid in an attacking position. The Aptychopsisis working as a protective shield, the dorsal plate is displaced to open the mouth with a radula on a short proboscis. The number of arms (ten) is based on Shigeno et al. 2008, 2010. The presence of well-developed eyes in orthocerids is based on the molecular study of Nautilus eyes (Ogura et al. 2013).
B, various views of Orthocerida with Aptychopsis. A small formation on the top of the orthocerid's head is an anterior part of a collar. In modern Nautilus it is a part of the protective hood (Shigeno et al. 2008), but in ancient cephalopods most likely it served to connect the head to the shell and to support collar folds (see Mironenko 2015).
(Andrey Atuchin, based on the sketch by A. A. Mironenko).

 
Aleksandr A. Mironenko. 2021. Early Palaeozoic Discinocarina: A Key to the Appearance of Cephalopod Jaws. Lethaia: an international journal of palaeontology and stratigraphy54(4); 457-476. DOI: 10.1111/let.12414

[Crustacea • 2021] Thor dicaprio • A New, conspicuously coloured Shrimp (Decapoda: Caridea: Thoridae) from the Tropical western Atlantic, with Taxonomic Remarks on the T. amboinensis (De Man, 1888) Complex



Thor dicaprio
Anker & Baeza, 2021

 
Abstract
Thor amboinensis (De Man, 1888), known as “sexy shrimp” or “anemone squat shrimp” and popular among divers and aquarists, was previously believed to have a worldwide distribution, with populations throughout the tropical parts of the Indo-Pacific and Atlantic Ocean. However, consistent differences in some details of the colour pattern strongly suggest that T. amboinensis does not represent a single species, but a pantropical species complex. A recent phylogeographic analysis of T. amboinensis based on molecular data confirmed that this taxon is composed of at least five putative cryptic or pseudocryptic species. In the present study, a new cryptic species, Thor dicaprio sp. nov., is established for the western Atlantic populations previously referred to as T. amboinensis. The new species can be distinguished from all other members of the T. amboinensis complex by two differences in the colour pattern and a subtle difference in the size and setation of the appendix masculina, the latter yet to be confirmed. The conspicuous red-white banding of the antennal flagella appears to be the most diagnostic feature of the new species. In addition, T. dicaprio sp. nov. forms a genetically distinctive, homogeneous, tropical western Atlantic (TWA) clade, with the COI pairwise genetic distances from other clades ranging from 8.8% to 19.2%. The distribution of T. dicaprio sp. nov. includes the entire Caribbean Sea, parts of the Gulf of Mexico, Florida, Bahamas, Bermuda, as well as some offshore localities off northern and eastern Brazil. The main aspects and biology and ecological variability of T. dicaprio sp. nov. are discussed in the light of phylogeographic data presently available for the T. amboinensis complex.

Keywords: Crustacea, Caridea, Thor, cryptic species, coral reef, symbiosis, sea anemone, west Atlantic, Indo-Pacific


  


 


    


Arthur Anker and J. Antonio Baeza. 2021. Thor dicaprio sp. nov., A New, conspicuously coloured Shrimp from the Tropical western Atlantic, with Taxonomic Remarks on the T. amboinensis (De Man, 1888) Complex (Decapoda: Caridea: Thoridae). Zootaxa. 5039(4); 495-517. DOI: 10.11646/zootaxa.5039.4.3

   

Tuesday, September 21, 2021

[Botany • 2019] Zingiber dimapurense (Zingiberaceae, section Cryptanthium) • A New Species from Nagaland, India


Zingiber dimapurense N.Odyuo, D.K.Roy & A.A.Mao, 

in Odyuo, Roy & Mao, 2019. 

Abstract
A new species of Zingiber section Cryptanthium Horaninow (Zingiberaceae), Zingiber dimapurense N.Odyuo, D.K.Roy & A.A.Mao, from Nagaland, Northeastern India is described and illustrated. Morphological diagnostic characters of closely related congeners are discussed.

Keywords: NE India, new species, Zingiberaceae, Zingiber section Cryptanthium

Figure 1. Zingiber dimapurense N.Odyuo, D.K.Roy & A.A.Mao:
 A. Habit. B. Mid portion of Leafy shoots. C. Petiole and ligule. D. Ligule, frontal view. E. Lamina surface beneath. F. & G. Inflorescences. H. Basal portion of Leafy shoots with rhizome and inflorescences.
[Photographed by D.K. Roy].

Figure 2. Zingiber dimapurense N.Odyuo, D.K.Roy & A.A.Mao:
A. Inflorescences. B. Transverse section of Rhizome, with an inflorescence. C. A flower with bracteole. D. A flower with calyx. E. Floral bract. F. Bracteole. G. Calyx. H. Dorsal corolla lobe. I. Lateral corolla lobes. J. Labellum (frontal view). K. Labellum (dorsal view). L. Stamen with style and stigma. M. Pistil, with epigynous glands. N. Ovary, with epigynous glands. O. Transverse section of ovary. P. Stigma. Q. Pollens.
[Photographed by D.K. Roy].


Zingiber dimapurense N.Odyuo, D.K.Roy & A.A.Mao

The new species is similar to Z. mizoramensis Ram.Kumar, Sushil K.Singh & S.Sharma in creamy white bracteoles with purplish red tinges, ovate-lanceolate to lanceolate, subequal, purplish pink corolla lobes with white base and creamy white anther crest with purplish apex and to Z. skornickovae N.S.Lý in hairy ligule and petiole, adaxially pubescent lamina, dorsally densely pubescent bracts and in pubescent calyx and corolla tube, but differs from them in leathery, densely hairy, to 1 cm long ligule, comparatively larger petiole to 1 cm long, elliptic-lanceolate lamina, obovate spike with 15–28 floral bracts, oblanceolate to oblongoblanceolate, pale green to creamy white bracts with purplish red blotches at apex and along margins, apically bidentate calyx, ovate-lanceolate, white labellum with dense dark purplish red blotches and acuminate apex and in triangular to ovatelanceolate, white lateral staminodes.

Etymology: The specific epithet refers to the place of occurrence of this species.


Nripemo Odyuo, Dilip Kr. Roy and A. A. Mao. 2019. Zingiber dimapurense (Zingiberaceae), A New Species from Nagaland, India. NeBIO. 10(2); 59-65. 


  

  

[Ichthyology • 2021] Cylix tupareomanaia • A New Genus and Species of Pygmy Pipehorse (Teleostei, Syngnathidae) from Taitokerau Northland, Aotearoa New Zealand, with a Redescription of Acentronura Kaup, 1853 and Idiotropiscis Whitley, 1947


Cylix tupareomanaia Short, Trnski, & Ngātiwai,

in Short & Trnski, 2021.
 
Abstract
Cylix tupareomanaia, new genus and species, is described from three specimens (35.5–55.5 mm SL), collected from rocky reefs at 12–17 m depth from Taitokerau Northland, New Zealand. The new taxon shares morphological synapomorphies with the superficially similar Australian endemic Idiotropiscis and Indo-Pacific Acentronura, including head angled ventrally approximately 25° from the principal body axis, enclosed brood pouch, brood pouch plates, prehensile tail, and absence of caudal fin. Cylix tupareomanaia, new genus and species, however, is distinguishable from all other members of the Syngnathidae by the following combination of bony autapomorphic characters: a cup-like crest present anterodorsally on the supraoccipital; and large conspicuous midventral conical spines on the cleithral symphysis and first trunk ring between the pectoral-fin bases. The new species can be further differentiated by genetic divergence in the mitochondrial COX1 gene from Acentronura breviperula, A. tentaculata, Idiotropiscis australe, and I. lumnitzeri (estimated uncorrected p-distances of 19.5%, 20.4%, 17.9%, and 18.4%, respectively). A phylogenetic hypothesis from the analysis of two nuclear loci, 18S and TMO-4C4, supports the placement of C. tupareomanaia, new genus and species, as the sister taxon to a clade comprising the genera Acentronura and Idiotropiscis. Cylix tupareomanaia, new genus and species, represents the eighth member within the pygmy pipehorse clade to be described from the Indo-Pacific and the first new genus and species of syngnathid to be reported from New Zealand since 1921.

Cylix tupareomanaia.
(A) AIM MA122274, female, holotype shortly after death, 31.4 mm SL; Waiatapaua Bay, Whangaruru, Northland, New Zealand (photograph © Auckland Museum).
(B) NMNZ P.056154, female, paratype, shortly after death, 35.5 mm SL; Cavalli Islands, Northland, New Zealand (photograph © Irene Middleton).

Cylix tupareomanaia.
 (A) AIM MA122274, female, preserved holotype, 31.4 mm SL; Waiatapaua Bay, Whangaruru, Northland, New Zealand (photograph © Auckland Museum).
(B) NMNZ P.056154, female, preserved paratype, 35.5 mm SL; Cavalli Islands, Northland, New Zealand (photograph © Auckland Museum).
 (C) NMNZ P.046322, male, preserved paratype, 55.5 mm SL; east of Oturori Rock, Bay of Islands, Northland, New Zealand (photograph Graham Short).



µCT scan of Cylix tupareomanaia, NMNZ P.046322, male, paratype, 55.5 mm SL.
 (A, B) Anterolateral view of the head highlighting the bifurcated and cup-like crest present on the supraoccipital, continuous cleithral ring, and the strongly elevated ventrolateral bulge of the pectoral-fin base.
(C) Anterodorsal aspect of the neurocranium highlighting the bifurcated and cup-like pentamerous bony crest present on the supraoccipital.
 Abbreviations: FS, frontal spine; PFB, pectoral-fin base; SC, supraoccipital crest; SCL, supracleithrum.

Cylix tupareomanaia in situ.
 (A) AIM MA122274, female, holotype, Waiatapaua Bay, Whangaruru, Northland, New Zealand, 12 m depth (photograph © Shane Housham). (B) Waiatapaua Bay, Whangaruru, Northland, New Zealand, 12 m depth (photograph © Shane Housham).
(C) Waiatapaua Bay, Whangaruru, Northland, New Zealand, 12 m depth (photograph © Richard Smith). (D) Waiatapaua Bay, Whangaruru, Northland, New Zealand, 12 m depth (photograph © Irene Middleton).
(E) Waiatapaua Bay, Whangaruru, Northland, New Zealand, 12 m depth (photograph © Irene Middleton). (F) Poor Knights Islands, Northland, New Zealand, at 10 m depth (photograph © Kent Erickson).

Cylix, new genus
 Type species.—Cylix tupareomanaia, new species.

Diagnosis.—A genus of the Syngnathidae that shares numerous morphological synapomorphies with Acentronura and Idiotropiscis, including head angled ventrally approximately 25° from the principal body axis, enclosed brood pouch, brood pouch plates, prehensile tail, and absence of caudal fin. However, Cylix tupareomanaia, new species, differs from all other genera by unique anatomical features of the head, including: a distinct, cup-like crest present anterodorsally on the supraoccipital; and large and conspicuous medioventral conical spines on the cleithral symphysis and the first trunk ring between the pectoral-fin bases. It differs further in having the following combination of morphological characters: prominent supraoccipital; continuous cleithrum; prominent supracleithrum; anterior nuchal plate absent; posterior nuchal plate present with bony dorsomedial crest; large gap present between the supraoccipital and posterior nuchal plate; one to three dorsal spines at midline of snout, posteriormost of these spines large; one large double and rugose lateral head spine present below the cup-like supraoccipital crest; three small blunt lateral head spines on operculum; rim of orbit elevated dorsolaterally and strongly ventrally; two spines on cleithral ring; large rugose spine anterior to ventral third of pectoral-fin base; moderate-sized spine at ventral extent of head; small spine present posterolateral to the pelvic-fin base; four subdorsal spines, forming a square, the dorsal two enlarged.

Etymology.—The generic name Cylix is derived from the Greek kylix, meaning cup or chalice, in reference to the cup-like crest present on the head. Gender masculine.


Cylix tupareomanaia Short, Trnski, and Ngātiwai, new species
 
Common Names: Māori—Tu pare o manaia, 
English—Manaia Pygmy Pipehorse
 
Hippocampus jugumus: Kuiter, 2009: 93, figs. A, B (Poor Knights Islands, New Zealand).
Acentronura australe: Stewart, 2015: 1053, fig. 148.1 (Bay of Islands, New Zealand).
Idiotropiscis aotearoa: Perkins, 2017 (Whangaruru, New Zealand;  http://www.inspiredtodive.com/photo-blog/introducing-idiotropiscis-aotearoa).

Etymology.—The species epithet tupareomanaia is a neologism gifted by kaumātua (tribal elders) of Ngātiwai and references Home Point adjacent to the type locality, referred to by Ngātiwai as Tu Pare o Huia, meaning “the plume of the huia”; the huia was a bird that became extinct in the early 20th century. Tu Pare o Manaia translates as “the garland of the Manaia.” The pare, or garland, references the pentamerous head crest of the new species, and Manaia is the Māori name for a seahorse, and is also an ancestor that appears as a stylized figure used in Māori carvings representing a guardian.



Graham A. Short and Thomas Trnski. 2021. A New Genus and Species of Pygmy Pipehorse from Taitokerau Northland, Aotearoa New Zealand, with a Redescription of Acentronura Kaup, 1853 and Idiotropiscis Whitley, 1947 (Teleostei, Syngnathidae). Ichthyology & Herpetology. 109(3); 806-835 . DOI: 10.1643/i2020136

    

[Paleontology • 2021] First Record of A Late Jurassic Rhamphorhynchine Pterosaur (Pterosauria: Rhamphorhynchidae) from Gondwana


Hypothetical reconstruction of Oxfordian rhamphorhinchids: MUHNCAL.20165 (Rhamphorhynchinae gen. et sp. indet.), Cerro Campamento Formation, Chile

in Alarcón-Muñoz, Otero, Soto-Acuña, ... et Rojas, 2021. 

We describe partial remains of a non-pterodactyloid pterosaur from Upper Jurassic levels of the Atacama Desert in northern Chile. The material includes a left humerus, a possible dorsal vertebra, and the shaft of a wing phalanx, all preserved in three dimensions and likely belonging to a single individual. The humerus has a hatchet-shaped deltopectoral crest, proximally positioned, and its shaft is markedly anteriorly curved, which are characteristic features of the clade Rhamphorhynchidae. In addition, the presence of a groove that runs along the caudal surface of the phalanx, being flanked by two asymmetric crests, is a distinctive feature of the clade Rhamphorhynchinae, which includes such genera as Rhamphorhynchus and Nesodactylus. Previous to this research, known records of Rhamphorhynchinae were restricted to Laurasia; thus, the specimen studied here represents the first evidence of this group found to date in Gondwana. Associated ammonoids allow us to assign the material to a middle Oxfordian age, which makes this specimen the oldest known pterosaur found in Chile, and the first of Oxfordian age in Gondwana. This discovery suggests that the clade Rhamphorhynchidae had a global distribution during the Late Jurassic.

Key words: Pterosauria, Rhamphorhynchidae, Rhamphorhynchinae, Oxfordian, Chile, Laurasia, Gondwana.



Systematic palaeontology
Diapsida Osborn, 1903
Archosauria Cope, 1869

Pterosauria Kaup, 1834
Breviquartossa Unwin, 2003

Rhamphorhynchidae Seeley, 1870
Rhamphorhynchinae Nopcsa, 1928

Rhamphorhynchinae gen. et sp. indet.

Fig. 3. Rhamphorhynchinae gen. et sp. indet. (MUHNCAL.20165) from Cerritos Bayos, west Calama, Chile; Cerro Campamento Formation, middle Oxfordian.
 Left humerus in dorsal (A1 , A5), posterodorsal (A2 , A6), posterior (A3 , A7), and ventral (A4 , A8) views,
photographs (A1 -A4) and explanatory drawings (A5 -A8).

Fig. 7. Simplified map of the world during the Oxfordian. The dashed line represents the hypothetical route that would have allowed the dispersal of marine vertebrates and invertebrates between Tethys and South America during the Late Jurassic (Caribbean corridor).
The finds of Oxfordian rhamphorhinchids: MUHNCAL.20165 (Rhamphorhynchinae gen. et sp. indet.), Cerro Campamento Formation, Chile (circle);
Cacibupteryx caribensis (Gasparini et al. 2004) and Nesodactylus hesperius (Colbert et al. 1969), Jagua Formation, Cuba (square);
Rhamphorhynchinae gen. et sp. indet. (Lydekker 1890, O'Sullivan 2018), Oxford Clay Formation, UK (star);
 Qinglongopterus guoi (Lü et al. 2012), Tiaojishan Formation, China (triangle).
Modified map from Scotese (2014).



Jhonatan Alarcón-Muñoz, Rodrigo A. Otero, Sergio Soto-Acuña, Alexander O. Vargas, Jennyfer Rojas, and Osvaldo Rojas. 2021. First Record of A Late Jurassic Rhamphorhynchine Pterosaur from Gondwana. Acta Palaeontologica Polonica. in press. DOI: 10.4202/app.00805.2020


Investigadores U. de Chile identifican enigmático "dragón volador" del Jurásico por primera vez en el Hemisferio Sur

MUHNCAL, Museo de Historia Natural y Cultural del Desierto de Atacama, Calama, Antofagasta Region, Northern Chile

  

[Crustacea • 2021] Cherax latimanus • A New Burrow-dwelling Freshwater Crayfish (Decapoda, Parastacidae) from the mid-Murray River catchment, Australia


 Cherax latimanus
McCormack & Raadik, 2021


Abstract
A new species of freshwater crayfish in the southern hemisphere family Parastacidae is described from the Murray Darling Basin (MDB), eastern Australia. The Swamp Yabby, Cherax latimanus sp. nov., is found in the mid-Murray River area of the states of New South Wales and Victoria and is only the third species of Cherax found naturally occurring in the MDB. It is morphologically distinguished from all other species of Cherax by the presence of marginal mesial dactylar basal spines and extensive ventral propodal setation. It is found in sympatry with the widespread but morphologically similar Common Yabby, Cherax destructor Clark, 1936, but can be distinguished by a suite of morphometric and meristic characters that include a broad rostrum lacking an apical spine, very broad chelae with deep punctations on the lateral propodal edge and ventral propodal setation, two prominent dactylar teeth, one mesial carpal spine, dorsal meral spines present, no setae on carpal mesial margin, cervical spines absent or tiny, and by genetic data. Cherax latimanus is further diagnosed by its distinctive biology: it is not found in permanent aquatic habitats such as streams or billabongs, spending the majority of its time in extensive, terrestrial, burrow networks containing some water, in ephemerally wet habitats such as drainage lines, roadside drains, depressions, swamps and cleared areas of pasture in lowland to foothill areas. It is occasionally found in stream habitats but only during large flood events when burrow systems are inundated.

Keywords: Crustacea, taxonomy, Crustacea Cherax destructor, yabby, yabbie, morphology, Barmah, wetland, Murray River, Murray-Darling Basin


  Cherax latimanus sp. nov., holotype, NMV J74790, male, 63.6 mm OCL,
roadside drain on south-east side of Nelson Road (near Benalla), Victoria
(Image: Rob McCormack).

Cherax latimanus sp. nov.
Swamp Yabby

Etymology. From the Latin latus, meaning broadwide, and manus, meaning hand, in reference to its distinctive wide chelae, an obvious characteristic which separates it from the Common Yabby (Cherax destructor) with which it is broadly sympatrically found.
 Common name—Swamp Yabby, however, colloquially also referred to as Banjo Claw Yabby, Barmah Cray, Barmah Swamp Yabby, Broad Claw Yabby, Broad Palmed Yabby, Moon Claw Yabby, Mud Burrow Yabby, Spanner Yabby, Spanner Claw Cray, Spanner Claw Yabby, Swamp Cray, Swamp Yabby, or Swampies.


Robert B. McCormack and Tarmo A. Raadik. 2021. Cherax latimanus sp. nov., A New Burrow-dwelling Freshwater Crayfish (Decapoda, Parastacidae) from the mid-Murray River catchment, Australia. Zootaxa. 5026(3); 344-374. DOI: 10.11646/zootaxa.5026.3.2

Monday, September 20, 2021

[Paleontology • 2021] New Specimens provide insights into the Anatomy of the Dinosauriform Lewisuchus admixtus Romer, 1972 from the upper Triassic Levels of the Chañares Formation, NW Argentina


Lewisuchus admixtus Romer, 1972

in  Agnolín, Egli, ... et Novas, 2021.

 Abstract
Lewisuchus admixtus is an early dinosauriform described by Alfred Romer in 1972 on the basis of a single, incomplete skeleton, collected in lower Upper Triassic rocks of the renowned Chañares Formation, at the Los Chañares type-locality, La Rioja Province, north-western Argentina. Recent field explorations to the type-locality resulted in the discovery of two partial articulated skeletons, which provide significant novel information. The cranial bones, presacral series, femur, tibia, and proximal tarsals of the new specimens match the preserved overlapping anatomy of the holotype and previously referred specimens of L. admixtus, including the presence of unique combination of character states among dinosauriforms (anterior presacral column with additional ossification on the top of neural spines, dorsal neural spines fan-shaped, anterior surface of the astragalus with a dorsally curved groove, and an inflated area on the anterior portion of the medial surface of this bone). This new information improves our understanding of the anatomy and taxonomy of early dinosauriforms and reinforces the role of Argentinean beds on the study of the origin of dinosaurs.

Keywords: Archosauria, Dinosauriformes, Late Triassic, Lewisuchus admixtus, South America


Lewisuchus admixtus.
preserved bones of PULR V-111. Scale bar: 2 cm.  

Posterior cervical and anterior dorsal vertebrae of Lewisuchus admixtus (PULR V-111)


CONCLUSIONS: 
New specimens reported here add valuable information on the anatomy of Lewisuchus admixtus. Outstanding novel features described here for this taxon include an iliac portion of the acetabulum that is medially closed, elongated ischium and pubis (representing at least 2/3 of the femoral length), fan-shaped dorsal neural spines with a spine tables, and gastralia well separated from one another. Besides, the cranial bones, presacral series, femur, tibia, and proximal tarsals of the new specimens match the preserved overlapping anatomy of the holotype of L. admixtus and some of the specimens previously referred to “Pseudolagosuchus major” (e.g., MACN-Pv 18954), including the presence of unique combination of character states among dinosauriforms. This provides stronger evidence for the association of specimens that currently form the hypodigm of L. admixtus. An improved understanding of the anatomy and taxonomy of the Chañares Formation dinosauriforms is crucial to shed new lights on the phylogenetic relationships among nondinosaurian dinosauriforms and the dawn of dinosaur evolution.


Federico Agnolín, Federico Brissón Egli, Martín D. Ezcurra, Max C. Langer and Fernando Novas. 2021. New Specimens provide insights into the Anatomy of the Dinosauriform Lewisuchus admixtus Romer, 1972 from the upper Triassic levels of the Chañares Formation, NW Argentina. The Anatomical Record. DOI: 10.1002/ar.24731